The road and construction sectors consume a large number of natural resources and energy, contributing significantly to waste generation and greenhouse gas emissions (GHG). The use of recycled aggregate from construction and demolition waste as a substitute for virgin aggregate is a current practice in the construction of new road sections. Additionally, in recent years, there has been an increasing focus on finding alternatives to bitumen for binders used in asphalt mixes. This study investigates and compares the impacts associated with two porous asphalt mixtures produced with CDW aggregates, virgin aggregates, and a polyolefin-based synthetic transparent binder through an LCA methodology. A cradle-to-gate approach was employed. Model characterization for calculating the potential environmental impacts of each porous asphalt mixture was performed using the ReCipe 2016 assessment method at the midpoint and endpoint levels. The results are presented with reference to a baseline scenario corresponding to a porous asphalt mixture, confirming the benefits associated with the use of recycled aggregates and in some cases the benefits of not using bitumen-based binders. This work contributes to the understanding of the importance of choosing the least environmentally damaging solution during the production or rehabilitation of road pavement infrastructure.

Over the past decade, numerous studies have explored the incorporation of recycled aggregates into asphalt concrete to reduce the environmental impacts associated with the production of hot mix asphalt (HMA). Nonetheless, only a limited number of these studies have specifically investigated the substitution of waste silt for limestone fillers. This study seeks to enhance understanding of the environmental implications of using waste silt in asphalt concrete pavement, applying the life cycle assessment (LCA) methodology. The analysis includes both 'cradle-to-gate' and 'cradle-to-grave' approaches to compare the environmental impacts of four different asphalt mixtures: 1) a control mixture with virgin aggregates, 2) a mixture incorporating silt, 3) a mixture with calcinated waste silt, and 4) a mixture with flash calcinated waste silt. The environmental assessment employs the non-renewable cumulative energy demand (nr-CED) and global warming potential (GWP) as primary indicators, spanning a projected lifecycle of 30 years. Furthermore, the ReCiPe midpoint method is utilized to focus on the most critical environmental indicators, including terrestrial, marine, and freshwater ecotoxicity, human carcinogenic and non-carcinogenic toxicity, and land use impacts. Preliminary results indicate that while the recycled mixtures show increased environmental benefits per kilogram of asphalt concrete produced compared to the control mixture during the production phase, the longevity of the control mixture surpasses that of the recycled alternatives over the complete 30-year lifecycle, resulting in lower overall environmental burdens.